Problem: Simplify the following expression: $k = \dfrac{6bc - 2c^2}{2ac} - \dfrac{6bc + c^2}{2ac}$ You can assume $a,b,c \neq 0$.
Solution: Since the expressions have the same denominator we simply combine the numerators: $k = \dfrac{6bc - 2c^2 - (6bc + c^2)}{2ac}$ $k = \dfrac{-3c^2}{2ac}$ The numerator and denominator have a common factor of $c$, so we can simplify $k = \dfrac{-3c}{2a}$